Organosilane precursors for ALD/CVD silicon-containing film applications

ABSTRACT

Disclosed are Si-containing thin film forming precursors, methods of synthesizing the same, and methods of using the same to deposit silicon-containing films using vapor deposition processes for manufacturing semiconductors, photovoltaics, LCD-TFT, flat panel-type devices, refractory materials, or aeronautics.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 371 of International PCT ApplicationPCT/US2013/051249, filed Jul. 19, 2013, which claims priority to U.S.provisional application No. 61/674,103, filed Jul. 20, 2012, the entirecontents of which are incorporated herein by reference.

TECHNICAL FIELD

Disclosed are Si-containing thin film forming precursors, methods ofsynthesizing the same, and methods of using the same to depositsilicon-containing films using vapor deposition processes formanufacturing semiconductors, photovoltaics, LCD-TFT, flat panel-typedevices, refractory materials, or aeronautics.

BACKGROUND

Si-containing thin films are used widely in the semiconductor,photovoltaic, LCD-TFT, flat panel-type device, refactory material, oraeronautic industries. Si-containing thin films may be used, forexample, as dielectric materials having electrical properties which maybe insulating (SiO₂, SiN, SiCN, SiCOH, MSiOx, wherein M is Hf, Zr, Ti,Nb, Ta, or Ge and x is greater than zero), Si-containing thin films maybe used as conducting films, such as metal silicides or metal siliconnitrides. Due to the strict requirements imposed by downscaling ofelectrical device architectures towards the nanoscale (especially below28 nm node), increasingly fine-tuned molecular precursors are requiredwhich meet the requirements of volatility (for ALD process), lowerprocess temperatures, reactivity with various oxidants and low filmcontamination, in addition to high deposition rates, conformality andconsistency of films produced.

It is well known that silane (SiH₄) can be used for thermal CVD. Howeverthis molecule is pyrophoric which makes this room temperature gas achallenge to handle safely. CVD methods employing halosilanes (such asdichlorosilane SiH₂Cl₂) have been used. However, these may require longpurge times, cause halogen contamination of the films and particleformation (from ammonium chloride salts), and even damage certainsubstrates resulting in undesirable interfacial layer formation.Partially replacing halogen with alkyl groups may yield someimprovement, but at a cost of detrimental carbon contamination withinthe film.

Organoaminosilanes have been used as precursors for CVD of Si-containingfilms. U.S. Pat. No. 7,192,626 to Dussarrat et al. reports the use oftrisilylamine N(SiH₃)₃ for deposition of SiN films. Other reportedprecursors include diisopropylaminosilane [SiH₃(NiPr₂)] and analogousSiH₃(NR₂) compounds (see, e.g., U.S. Pat. No. 7,875,312 to Thridandam etal.) and phenylmethylaminosilane [SiH₃(NPhMe)] and related substitutedsilylanilines (see, e.g., EP 2392691 to Xiao et al.).

Another related class of Si precursors for CVD of Si-containing films isgiven by the general formula (R¹R²N)_(x)SiH_(4-x) wherein x is between 1and 4 and the R substituents are independently H, C1-C6 linear,branched, or cyclic carbon chains (see, e.g., WO2006/097525 to Dussarratet al.).

Hunks et al. disclose a wide range of Si-containing precursors inUS2010/0164057, including silicon compounds having the formulaR_(4-x)SiL_(x), wherein x is an integer having a value from 1 to 3; Rmay be selected from H, branched and unbranched C1-C6 alkyl, C3-C8cycloalkyl, and C6-C13 aryl groups; and L may be selected fromisocyanato, methylethylketoxime, trifluoroacetate, triflate, acyloxy,β-diketiminate, β-di-iminate, amidinate, guanidinate, alkylamino,hydride, alkoxide, or formate ligands. Pinnavaia et al. claim a methodfor the preparation of a porous synthetic, semi-crystalline hybridorganic-inorganic silicon oxide composition from silicon acetylacetonateand silicon 1,3-diketonate precursors (U.S. Pat. No. 6,465,387).

Despite the wide range of choices available for the deposition of Sicontaining films, additional precursors are continuously sought toprovide device engineers the ability to tune manufacturing processrequirements and achieve films with desirable electrical and physicalproperties.

NOTATION AND NOMENCLATURE

Certain abbreviations, symbols, and terms are used throughout thefollowing description and claims, and include:

As used herein, the indefinite article “a” or “an” means one or more.

As used herein, the term “independently” when used in the context ofdescribing R groups should be understood to denote that the subject Rgroup is not only independently selected relative to other R groupsbearing the same or different subscripts or superscripts, but is alsoindependently selected relative to any additional species of that same Rgroup. For example in the formula MR % (NR²R³)_((4-x)), where x is 2 or3, the two or three R¹ groups may, but need not be identical to eachother or to R² or to R³. Further, it should be understood that unlessspecifically stated otherwise, values of R groups are independent ofeach other when used in different formulas.

As used herein, the term “alkyl group” refers to saturated functionalgroups containing exclusively carbon and hydrogen atoms. Further, theterm “alkyl group” refers to linear, branched, or cyclic alkyl groups.Examples of linear alkyl groups include without limitation, methylgroups, ethyl groups, propyl groups, butyl groups, etc. Examples ofbranched alkyls groups include without limitation, t-butyl. Examples ofcyclic alkyl groups include without limitation, cyclopropyl groups,cyclopentyl groups, cyclohexyl groups, etc.

As used herein, the term “aryl” refers to aromatic ring compounds whereone hydrogen atom has been removed from the ring. As used herein, theterm “heterocycle” refers to a cyclic compound that has atoms of atleast two different elements as members of its ring.

As used herein, the abbreviation “Me” refers to a methyl group; theabbreviation “Et” refers to an ethyl group; the abbreviation “Pr” refersto any propyl group (i.e., n-propyl or isopropyl); the abbreviation“iPr” refers to an isopropyl group; the abbreviation “Bu” refers to anybutyl group (n-butyl, iso-butyl, t-butyl, sec-butyl); the abbreviation“tBu” refers to a tert-butyl group; the abbreviation “sBu” refers to asec-butyl group; the abbreviation “iBu” refers to an iso-butyl group;the abbreviation “Ph” refers to a phenyl group; the abbreviation “Am”refers to any amyl group (iso-amyl, sec-amyl, tert-amyl); theabbreviation “Hex” refers to a 6 member alkyl group, which may belinear, branched or cyclic; and the abbreviation “Cy” refers to a cyclicalkyl group (cyclobutyl, cyclopentyl, cyclohexyl, etc.).

As used herein, the acronym “SRO” stands for a Strontium Ruthenium Oxidefilm; the acronym “HCDS” stands for hexachlorodisilane; and the acronym“PODS” stands for pentachlorodisilane.

The standard abbreviations of the elements from the periodic table ofelements are used herein. It should be understood that elements may bereferred to by these abbreviations (e.g., Si refers to silicon, N refersto nitrogen, O refers to oxygen, C refers to carbon, etc.).

SUMMARY

Disclosed are organosilane molecules having the following formula:

wherein each L¹ and L² is a nitrogen atom; L¹ and L² being joinedtogether via a carbon bridge having two to three carbon atoms; L¹, L²and the carbon bridge forming a monoanionic ligand bonded to silicon.The disclosed molecules may have one or more of the following aspects:

-   -   the organosilane molecule having the following formula:

wherein R¹, R², R³, R⁴, and R⁵ may each independently be H, a C1 to C6alkyl group, or a C3-C20 aryl or heterocycle;

-   -   R¹ and R² and/or R² and R³ and/or R³ and R⁴ and/or R⁴ and R⁵        joined to form cyclic chains;    -   the organosilane molecule being H₃Si(-(iPr)N—C₃H₃—N(iPr)-);    -   the organosilane molecule having the following formula:

wherein R¹, R², R³, R⁴, R⁵, and R⁶ may each independently be H, a C1 toC6 alkyl group, or a C3-C20 aryl or heterocycle;

-   -   R¹ and R² and/or R² and R³ and/or R³ and R⁴ and/or R⁴ and R⁵        and/or R⁵ and R⁶ joined to form cyclic chains;    -   the organosilane molecule being H₃Si(-(iPr)N—C₃H₆—N(Me)₂-);    -   the organosilane molecule having the following formula:

wherein R¹, R², R³, R⁴, and R⁵ may each independently be H, a C1 to C6alkyl group, or a C3-C20 aryl or heterocycle;

-   -   R¹ and R² and/or R² and R³ and/or R³ and R⁴ joined to form        cyclic chains;    -   the organosilane molecule being H₃Si(-(iPr)N—CH₂CH═N(iPr)-);    -   the organosilane molecule having the following formula:

wherein R¹, R², R³, R⁴, and R⁵ may each independently be H, a C1 to C6alkyl group, or a C3-C20 aryl or heterocycle;

-   -   R¹ and R² and/or R² and R³ and/or R³ and R⁴ and/or R⁴ and R⁵        joined to form cyclic chains; and    -   the organosilane molecule being H₃Si((iPr)NC₂H₄N(Me)₂.

Also disclosed are Si-containing thin film forming precursors having thefollowing formula:

wherein each L¹ and L² is a nitrogen atom; L¹ and L² being joinedtogether via a carbon bridge having two to three carbon atoms; L¹, L²and the carbon bridge forming a monoanionic ligand bonded to silicon.The disclosed molecules may have one or more of the following aspects:

-   -   the Si-containing thin film forming precursor having the        following formula:

wherein R¹, R², R³, R⁴, and R⁵ may each independently be H, a C1 to C6alkyl group, or a C3-C20 aryl or heterocycle;

-   -   R¹ and R² and/or R² and R³ and/or R³ and R⁴ and/or R⁴ and R⁵        joined to form cyclic chains;    -   the Si-containing thin film forming precursor being        H₃Si(-(iPr)N—C₃H₃—N(iPr)-);    -   the Si-containing thin film forming precursor having the        following formula:

wherein R¹, R², R³, R⁴, R⁵, and R⁶ may each independently be H, a C1 toC6 alkyl group, or a C3-C20 aryl or heterocycle;

-   -   R¹ and R² and/or R² and R³ and/or R³ and R⁴ and/or R⁴ and R⁵        and/or R⁵ and R⁶ joined to form cyclic chains;    -   the Si-containing thin film forming precursor being        H₃Si(-(iPr)N—C₃H₆—N(Me)₂-);    -   the Si-containing thin film forming precursor having the        following formula:

wherein R¹, R², R³, R⁴, and R⁵ may each independently be H, a C1 to C6alkyl group, or a C3-C20 aryl or heterocycle;

-   -   R¹ and R² and/or R² and R³ and/or R³ and R⁴ joined to form        cyclic chains;    -   the Si-containing thin film forming precursor being        H₃Si(-(iPr)N—CH₂CH═N(iPr)-);    -   the Si-containing thin film forming precursor having the        following formula:

wherein R¹, R², R³, R⁴, and R⁵ may each independently be H, a C1 to C6alkyl group, or a C3-C20 aryl or heterocycle;

-   -   R¹ and R² and/or R² and R³ and/or R³ and R⁴ and/or R⁴ and R⁵        joined to form cyclic chains; and    -   the Si-containing thin film forming precursor being        H₃Si((iPr)NC₂H₄N(Me)₂.

Also disclosed are methods of depositing a Si-containing layer on asubstrate.

At least one organosilane precursor disclosed above is introduced into areactor having at least one substrate disposed therein. At least part ofthe organosilane precursor is deposited onto the at least one substrateto form a Si-containing layer using a vapor deposition method. Thedisclosed methods may have one or more of the following aspects:

-   -   introducing into the reactor a vapor comprising at least one        second precursor;    -   an element of the at least one second precursor being selected        from the group consisting of group 2, group 13, group 14,        transition metal, lanthanides, and combinations thereof;    -   the element of the at least one second precursor being selected        from Mg, Ca, Sr, Ba, Zr, Hf, Ti, Nb, Ta, Al, Si, Ge, Y, or        lanthanides;    -   introducing into the reactor at least one co-reactant;    -   the co-reactant being selected from the group consisting of O₂,        O₃, H₂O, H₂O₂, NO, NO₂, a carboxylic acid, radicals thereof, and        combinations thereof;    -   the co-reactant being plasma treated oxygen;    -   the co-reactant being ozone;    -   the Si-containing layer being a silicon oxide layer;    -   the co-reactant being selected from the group consisting of H₂,        NH₃, (SiH₃)₃N, hydridosilanes (such as SiH₄, Si₂H₆, Si₃H₈,        Si₄H₁₀, Si₅H₁₀, Si₆H₁₂), chlorosilanes and chloropolysilanes        (such as SiHCl₃, SiH₂Cl₂, SiH₃Cl, Si₂Cl₆, Si₂HCl₅, Si₃Cl₈),        alkysilanes (such as Me₂SiH₂, Et₂SiH₂, MeSiH₃, EtSiH₃),        hydrazines (such as N₂H₄, MeHNNH₂, MeHNNHMe), organic amines        (such as NMeH₂, NEtH₂, NMe₂H, NEt₂H, NMe₃, NEt₃, (SiMe₃)₂NH),        pyrazoline, pyridine, B-containing molecules (such as B₂H₆,        9-borabicylo[3,3,1]none, trimethylboron, triethylboron,        borazine), alkyl metals (such as trimethylaluminum,        triethylaluminum, dimethylzinc, diethylzinc), radical species        thereof, and mixtures thereof.    -   the co-reactant being selected from the group consisting of H₂,        NH₃, SiH₄, Si₂H₆, Si₃H₈, SiH₂Me₂, SiH₂Et₂, N(SiH₃)₃, hydrogen        radicals thereof, and mixtures thereof;    -   the co-reactant being plasma-treated;    -   the co-reactant being remote plasma-treated;    -   the co-reactant not being plasma-treated;    -   the co-reactant being H₂;    -   the co-reactant being NH₃;    -   the co-reactant being HCDS;    -   the co-reactant being PODS;    -   the co-reactant being tetrachlorosilane;    -   the co-reactant being trichlorosilane;    -   the co-reactant being hexachlorocyclohexasilane;    -   the vapor deposition process being a chemical vapor deposition        process;    -   the vapor deposition process being an atomic layer deposition        (ALD) process;    -   the vapor deposition processing being a spatial ALD process;    -   the silicon-containing layer being Si;    -   the silicon-containing layer being SiO₂;    -   the silicon-containing layer being SiN;    -   the silicon-containing layer being SiON;    -   the silicon-containing layer being SiCN; and    -   the silicon-containing layer being SiCOH.

DESCRIPTION OF PREFERRED EMBODIMENTS

Disclosed are Si-containing thin film forming precursors, methods ofsynthesizing the same, and methods of using the same to depositsilicon-containing films using vapor deposition processes formanufacturing semiconductors, photovoltaics, LCD-TFT, flat panel-typedevices, refractory materials, or aeronautics.

The disclosed Si-containing thin film forming precursors have thefollowing formula:

wherein each L¹ and L² is a nitrogen atom, L¹ and L² being joinedtogether via a carbon bridge having two or three carbon atoms; L¹, L²,and the carbon bridge form a monoanionic ligand bonded to silicon. Asillustrated in the formula, the L¹ and L² nitrogen atoms are bonded tothe silicon atom, resulting in a pentacoordinate Si(IV) center. Thecarbon atoms in the carbon bridge may be sp² hybridized, resulting in adelocalized charge across the monoanionic ligand. Alternatively, thecarbon atoms in the carbon bridge may be either sp3 hybridized or somecombination of sp2 and sp3 hybridized, resulting in a negative charge onone of L¹ or L² and resulting in a neutral charge on the other of L¹ orL². Each of the nitrogen and carbon atoms may independently besubstituted by H, C1-C6 alkyl groups, aryl groups, or heterocyclegroups.

The disclosed organosilane precursors may be more reactive than otherR_(4-x)SiL_(x) precursors due to hypercoordination at the silicon atom.In other words, although the silicon atom is +IV, the three hydrogenbonds and the monoanionic chelating ligand results in a total of 5 bondsto the silicon atom.

Due to their increased nitrogen content on the N—(C)n-N ligand, with nbeing 2 or 3, these molecules may be used to produce silicon-containingfilms that also contain nitrogen, such as SiN, SiCN, SiON, MSiN, orMSiON, wherein M is an element such as Hf, Zr, Ti, Nb, Ta, or Ge, or totune the amount of nitrogen in those films.

When the carbon bridge of the disclosed organosilane precursors includesthree (3) carbon atoms (i.e., —N—(C(R))₃—N—), the resulting precursorsare 3-diketiminatosilane compounds. Exemplary β-diketiminatosilaneprecursors have the following formula:

wherein R¹, R², R³, R⁴, and R⁵ may each independently be H, a C1 to C6alkyl group, or a C3-C20 aryl or heterocycle R¹ and R² and/or R² and R³and/or R³ and R⁴ and/or R⁴ and R⁵ may be joined to form cyclic chains.The three carbon atoms are sp² hybridized. If R¹ and R⁵ are the same andR² and R⁴ are the same (i.e., all Me, or R¹ and R⁵=Me and R² and R⁴=H),the resulting Fourier-Transform Infra Red (FTIR) spectra for thesemolecules will produce one peak for both of the N atoms due to thedelocalization of the electrons across the ligand.

Exemplary β-diketiminatosilane precursors with the above formulainclude:

Preferably, the β-diketiminatosilane precursor isH₃Si(-(iPr)N—C₃H₃—N(iPr)-).

When the carbon bridge of the disclosed organosilane precursors includesthree (3) carbon atoms (i.e., —N—(C(R))₃—N—), the resulting precursorsare aminosilylamine compounds. Exemplary aminosilylamine organosilaneprecursors have the following formula:

wherein R¹, R², R³, R⁴, R⁵, and R⁶ may each independently be H, a C1 toC6 alkyl group, or a C3-C20 aryl or heterocycle. One of ordinary skillin the art will recognize the implied H on the carbons in the structureabove, which has been left off due to space constraints. R¹ and R²and/or R² and R³ and/or R³ and R⁴ and/or R⁴ and R⁵ and/or R⁵ and R⁶ maybe joined to form cyclic chains. The three carbon atoms may be sp2 orsp3 hybridized. An anionic charge may be localized at the “top” nitrogenatom. The “bottom” nitrogen atom may form a dative bond to the Si atom.Due to the unsymmetrical nature of the ligand, the three carbon atomswill produce different peaks in nuclear magnetic resonance (NMR)spectra.

Exemplary aminosilylamine precursors with the above formula include:

Preferably, the aminosilylamine precursor is H₃Si(-(iPr)N—C₃H₆—N(Me)₂-).

The H₃Si[RN(CR)₃NR] or H₃Si[R₂N(CR)₃NR] precursors may be synthesized bycombining a hydrocarbon solution of SiXH₃, wherein X is Cl, Br, I, ortriflate (SO₃CF₃ ⁻), with a neat or hydrocarbon solution of the ligandcompound, such as Li[RN(CR)₃NR] or Li[R₂N(CR)₃NR], under atmosphere ofnitrogen, the outlet of the mixing flask being connected to an oilbubbler to inhibit backflow of air and moisture.

A second synthetic route to the disclosed H₃Si[RN(CR)₃NR] orH₃Si[R₂N(CR)₃NR] precursors is by reaction of the protonated ligandRN(CR)₃NHR or RHN(CR)₃NR₂ with either a neat or a hydrocarbon solutionof a dialkylaminosilane [SiH₃(NR₂)] performed under an inert atmosphere.

Alternatively, the disclosed H₃Si[RN(CR)₃NR] or H₃Si[R₂N(CR)₃NR]precursors may be synthesized by reaction of SiH_(n)Cl_(4-n) with asingle equivalent of the ligand compound (i.e., Li[RN(CR)₃NR] orLi[R₂N(CR)₃NR]) and subsequent reduction using a selected metal hydride,such as LAH (lithium aluminum hydride).

In all three synthesis routes, the resulting solution may be stirred atroom temperature overnight. Exemplary hydrocarbon solutions suitable forthese synthesis methods include diethyl ether, pentane, hexane, ortoluene. The resulting suspension is filtered and the resulting solutiondistilled to remove solvent. Purification of the resulting liquid orsolid is carried out by distillation or sublimation, respectively.Except for the ligand compounds Li[RN(CR)₃NR] or Li[R₂N(CR)₃NR], all ofthe starting materials are commercially available. The ligand compoundmay be synthesized by combining a hydrocarbon solution of metalorganicsalt (i.e., alkyl lithium) to a hydrocarbon solution of the appropriatediamine (i.e., R¹N═CR²—CR³—CR⁴—NHR⁵, R¹N═CR²—CR³═CR⁴—NHR⁵,R¹HN—CR²—CR³—CR⁴—NR⁵R⁶). One of ordinary skill in the art wouldrecognize that proper selection of the ligand will result in theunsaturated β-diketiminatosilane precursor or the saturatedaminosilylamine precursor.

When the carbon bridge of the disclosed organosilane precursors includestwo (2) carbon atoms (i.e., —N—(C(R))₂—N—, the resulting precursors areiminosilylamine compounds. Exemplary iminosilylamine organosilaneprecursors have the following formula:

wherein R¹, R², R³, and R⁴ may each independently be H, a C1 to C6 alkylgroup, or a C3-C20 aryl or heterocycle. One of ordinary skill in the artwill recognize the implied H on the carbon in the structure above, whichhas been left off due to space constraints. R¹ and R² and/or R² and R³and/or R³ and R⁴ may be joined to form cyclic chains. The two carbonatoms may be sp² or sp^(a) hybridized. The formula above illustrates ananionic charge localized at the “top” nitrogen atom. The “bottom”nitrogen atom having the double bond to C(R³) forms a dative bond to thesilicon atom. However, one of ordinary skill in the art will recognizethat the double bond may also be delocalized across the ring when thecarbon atoms are sp² hybridized. If R¹ and R⁴ are the same and R² and R³are the same (i.e., all Me, or R¹ and R⁴=Me and R² and R³=H), theresulting Fourier-transform Infra Red (FTIR) spectra for these moleculeswill produce one peak for both of the N atoms due to the delocalizationof the electrons across the ligand.

Exemplary iminosilylamine precursors with the above formula include:

Preferably the iminosilylamine is H₃Si(-(iPr)N—CH₂CH═N(iPr)-).

When the carbon bridge of the disclosed organosilane precursors includestwo (2) carbon atoms (i.e., —N—(C(R))₂—N—, the resulting precursors areaminosilylamine compounds. Exemplary aminosilylamine organosilaneprecursors have the following formula:

wherein R¹, R², R³, R⁴, and R⁵ may each independently be H, a C1 to C6alkyl group, or a C3-C20 aryl or heterocycle. One of ordinary skill inthe art will recognize the implied H on the carbons in the structureabove, which have been left off due to space constraints. R¹ and R²and/or R² and R³ and/or R³ and R⁴ and/or R⁴ and R⁵ may be joined to formcyclic chains. The two carbon atoms may be sp2 or sp3 hybridized. Ananionic charge may be localized at the nitrogen atom. The other nitrogenatom may form a dative bond to the Si atom. Due to the unsymmetricalnature of the ligand, the two carbon atoms will produce different peaksin nuclear magnetic resonance (NMR) spectra.

Exemplary aminosilylamine precursors with the above formula include:

Preferably, the aminosilylamine precursor is H₃Si((iPr)NC₂H₄N(Me)₂.

The H₃Si[RN(CR)₂NR] or H₃Si[R₂N(CR)₂NR] precursors may be synthesized bycombining a hydrocarbon solution of SiXH₃, wherein X is Cl, Br, I, ortriflate (SO₃CF₃), with a neat or hydrocarbon solution of the ligandcompound, such as Li[RN(CR)₂NR] or Li[R₂N(CR)₂NR], under atmosphere ofnitrogen, the outlet of the mixing flask being connected to an oilbubbler to inhibit backflow of air and moisture.

A second synthetic route to the disclosed H₃Si[RN(CR)₂NR] orH₃Si[R₂N(CR)₂NR] precursors is by reaction of the protonated ligandRN(CR)₂NHR or RHN(CR)₂NR₂ with either a neat or a hydrocarbon solutionof a dialkylaminosilane [SiH₃(NR₂)] performed under an inert atmosphere.

Alternatively, the disclosed H₃Si[RN(CR)₂NR] or H₃Si[R₂N(CR)₂NR]precursors may be synthesized by reaction of SiH_(n)Cl₄, with a singleequivalent of the ligand compound (i.e., Li[RN(CR)₂NR] orLi[R₂N(CR)₂NR]) and subsequent reduction using a selected metal hydride,such as LAH (lithium aluminum hydride).

In all three synthesis routes, the resulting solution may be stirred atroom temperature overnight. Exemplary hydrocarbon solutions suitable forthese synthesis methods include diethyl ether, pentane, hexane, ortoluene. The resulting suspension is filtered and the resulting solutiondistilled to remove solvent. Purification of the resulting liquid orsolid is carried out by distillation or sublimation, respectively.Except for the ligand compounds Li[RN(CR)₂NR] or Li[R₂N(CR)₂NR], all ofthe starting materials are commercially available. The ligand compoundmay be synthesized by combining a hydrocarbon solution of metalorganicsalt (i.e., alkyl lithium) to a hydrocarbon solution of the appropriatediamine (i.e., R¹N═CR²—CR³—NHR⁴, R¹HN—CR²—CR³—NR⁴R⁵). One of ordinaryskill in the art would recognize that proper selection of the ligandwill result in the saturated aminosilylamino or unsaturatediminosilylamino precursor.

Also disclosed are methods of using the disclosed organosilaneprecursors for vapor deposition methods. The disclosed methods providefor the use of the organosilane precursors for deposition ofsilicon-containing films. The disclosed methods may be useful in themanufacture of semiconductor, photovoltaic, LCD-TFT, or flat panel typedevices. The method includes: providing a substrate; providing a vaporincluding at least one of the disclosed organosilane precursors: andcontacting the vapor with the substrate (and typically directing thevapor to the substrate) to form a silicon-containing layer on at leastone surface of the substrate.

The disclosed methods also provide for forming a bimetal-containinglayer on a substrate using a vapor deposition process and, moreparticularly, for deposition of SiMO_(x) films, wherein x may be 0-4 andM is Ta, Hf, Nb, Mg, Al, Sr, Y, Ba, Ca, As, Sb, Bi, Sn, Pb, Co,lanthanides (such as Er), or combinations thereof. The disclosed methodsmay be useful in the manufacture of semiconductor, photovoltaic,LCD-TFT, or flat panel type devices. The method includes: providing asubstrate; providing a vapor including at least one of the disclosedorganosilane precursors and contacting the vapor with the substrate (andtypically directing the vapor to the substrate) to form a bimetal-containing layer on at least one surface of the substrate. Anoxygen source, such as O₃, O₂, H₂O, NO, H₂O₂, acetic acid, formalin,para-formaldehyde, oxygen radicals thereof, and combinations thereof,but preferably O₃ or plasma treated O₂ may also be provided with thevapor.

The disclosed organosilane precursors may be used to depositsilicon-containing films using any deposition methods known to those ofskill in the art. Examples of suitable deposition methods includewithout limitation, conventional chemical vapor deposition (CVD), lowpressure chemical vapor deposition (LPCVD), atomic layer deposition(ALD), pulsed chemical vapor deposition (P-CVD), thermal ALD, thermalCVD, plasma enhanced atomic layer deposition (PE-ALD), plasma enhancedchemical vapor deposition (PE-CVD), spatial ALD, or combinationsthereof. Preferably, the deposition method is ALD, spatial ALD, orPE-ALD.

The vapor of the organosilane precursor is introduced into a reactionchamber containing at least one substrate. The temperature and thepressure within the reaction chamber and the temperature of thesubstrate are held at conditions suitable for vapor deposition of atleast part of the organosilane precursor onto the substrate. In otherwords, after introduction of the vaporized precursor into the chamber,conditions within the chamber are such that at least part of thevaporized precursor is deposited onto the substrate to form thesilicon-containing film. A co-reactant may also be used to help information of the Si-containing layer.

The reaction chamber may be any enclosure or chamber of a device inwhich deposition methods take place, such as, without limitation, aparallel-plate type reactor, a cold-wall type reactor, a hot-wall typereactor, a single-wafer reactor, a multi-wafer reactor, or other suchtypes of deposition systems. All of these exemplary reaction chambersare capable of serving as an ALD reaction chamber. The reaction chambermay be maintained at a pressure ranging from about 0.5 mTorr to about 20Torr. In addition, the temperature within the reaction chamber may rangefrom about 20° C. to about 600° C. One of ordinary skill in the art willrecognize that the temperature may be optimized through mereexperimentation to achieve the desired result.

The temperature of the reactor may be controlled by either controllingthe temperature of the substrate holder or controlling the temperatureof the reactor wall. Devices used to heat the substrate are known in theart. The reactor wall is heated to a sufficient temperature to obtainthe desired film at a sufficient growth rate and with desired physicalstate and composition. A non-limiting exemplary temperature range towhich the reactor wall may be heated includes from approximately 20° C.to approximately 600° C. When a plasma deposition process is utilized,the deposition temperature may range from approximately 20° C. toapproximately 550° C. Alternatively, when a thermal process isperformed, the deposition temperature may range from approximately 300°C. to approximately 600° C.

Alternatively, the substrate may be heated to a sufficient temperatureto obtain the desired silicon-containing film at a sufficient growthrate and with desired physical state and composition. A non-limitingexemplary temperature range to which the substrate may be heatedincludes from 150° C. to 600° C. Preferably, the temperature of thesubstrate remains less than or equal to 500° C.

The type of substrate upon which the silicon-containing film will bedeposited will vary depending on the final use intended. In someembodiments, the substrate may be a patterned photoresist film made ofhydrogenated carbon, for example CH_(x), wherein x is greater than zero.In some embodiments, the substrate may be chosen from oxides which areused as dielectric materials in MIM, DRAM, or FeRam technologies (forexample, ZrO₂ based materials, HfO₂ based materials, TiO₂ basedmaterials, rare earth oxide based materials, ternary oxide basedmaterials, etc.) or from nitride-based films (for example, TaN) that areused as an oxygen barrier between copper and the low-k layer. Othersubstrates may be used in the manufacture of semiconductors,photovoltaics, LCD-TFT, or flat panel devices. Examples of suchsubstrates include, but are not limited to, solid substrates such asmetal nitride containing substrates (for example, TaN, TiN, WN, TaCN,TiCN, TaSiN, and TiSiN); insulators (for example, SiO₂, Si₃N₄, SiON,HfO₂, Ta₂O₅, ZrO₂, TiO₂, Al₂O₃, and barium strontium titanate); or othersubstrates that include any number of combinations of these materials.The actual substrate utilized may also depend upon the specificprecursor embodiment utilized. In many instances though, the preferredsubstrate utilized will be selected from hydrogenated carbon, TiN, SRO,Ru, and Si type substrates, such as polysilicon or crystalline siliconsubstrates.

The disclosed organosilane precursors may be supplied either in neatform or in a blend with a suitable solvent, such as toluene, ethylbenzene, xylene, mesitylene, decane, dodecane, octane, hexane, pentane,tertiary amines, acetone, tetrahydrofuran, ethanol, ethylmethylketone,1,4-dioxane, or others. The disclosed precursors may be present invarying concentrations in the solvent. For example, the resultingconcentration may range from approximately 0.05 M to approximately 2 M.

The neat or blended organosilane precursors are introduced into areactor in vapor form by conventional means, such as tubing and/or flowmeters. The precursor in vapor form may be produced by vaporizing theneat or blended precursor solution through a conventional vaporizationstep such as direct vaporization, distillation, by bubbling, or by usinga sublimator such as the one disclosed in PCT Publication WO2009/087609to Xu et al. The neat or blended precursor may be fed in liquid state toa vaporizer where it is vaporized before it is introduced into thereactor. Alternatively, the neat or blended precursor may be vaporizedby passing a carrier gas into a container containing the precursor or bybubbling the carrier gas into the precursor. The carrier gas mayinclude, but is not limited to, Ar, He, or N₂, and mixtures thereof.Bubbling with a carrier gas may also remove any dissolved oxygen presentin the neat or blended precursor solution. The carrier gas and precursorare then introduced into the reactor as a vapor.

If necessary, the container may be heated to a temperature that permitsthe organosilane precursor to be in its liquid phase and to have asufficient vapor pressure. The container may be maintained attemperatures in the range of, for example, 0-150° C. Those skilled inthe art recognize that the temperature of the container may be adjustedin a known manner to control the amount of organosilane precursorvaporized.

In addition to the disclosed precursor, a reaction gas may also beintroduced into the reactor. The reaction gas may be an oxidizing agentsuch as one of O₂; O₃; H₂O; H₂O₂; oxygen containing radicals such as O.or OH.; NO; NO₂; carboxylic acids such as formic acid, acetic acid,propionic acid; radical species of NO, NO₂, or the carboxylic acids;para-formaldehyde; and mixtures thereof. Preferably, the oxidizing agentis selected from the group consisting of O₂, O₃, H₂O, H₂O₂, oxygencontaining radicals thereof such as O. or OH., and mixtures thereof.Preferably, when an ALD process is performed, the co-reactant is plasmatreated oxygen, ozone, or combinations thereof. When an oxidizing gas isused, the resulting silicon containing film will also contain oxygen.

Alternatively, the reaction gas may be a reducing agent such as one ofH₂, NH₃, (SiH₃)₃N, hydridosilanes (such as SiH₄, Si₂H₆, Si₃H₈, Si₄H₁₀,Si₅H₁₀, Si₆H₁₂), chlorosilanes and chloropolysilanes (such as SiHCl₃,SiH₂Cl₂, SIH₃Cl, Si₂Cl₆, Si₂HCl₅, Si₃Cl₈), alkylsilanes (such as(CH₃)₂SiH₂, (C₂H₅)₂SiH₂, (CH₃)SiH₃, (C₂H₅)SiH₃), hydrazines (such asN₂H₄, MeHNNH₂, MeHNNHMe), organic amines (such as N(CH₃)H₂, N(C₂H₅)H₂,N(CH₃)₂H, N(C₂H₅)₂H, N(CH₃)₃, N(C₂H₅)₃, (SiMe₃)₂NH), pyrazoline,pyridine, B-containing molecules (such as B₂H₆,9-borabicyclo[3,3,1]none, trimethylboron, triethylboron, borazine),alkyl metals (such as trimethylaluminum, triethylaluminum, dimethylzinc,diethylzinc), radical species thereof, and mixtures thereof. Preferably,the reducing agent is H₂, NH₃, SiH₄, Si₂H₆, Si₃H₈, SiH₂Me₂, SiH₂Et₂,N(SiH₃)₃, hydrogen radicals thereof, or mixtures thereof. When areducing agent is used, the resulting silicon containing film may bepure Si.

The reaction gas may be treated by a plasma, in order to decompose thereaction gas into its radical form. N₂ may also be utilized as areducing agent when treated with plasma. For instance, the plasma may begenerated with a power ranging from about 50 W to about 500 W,preferably from about 100 W to about 200 W. The plasma may be generatedor present within the reactor itself. Alternatively, the plasma maygenerally be at a location removed from the reactor, for instance, in aremotely located plasma system. One of skill in the art will recognizemethods and apparatus suitable for such plasma treatment.

The disclosed organosilane precursors may also be used with a halosilaneor polyhalodisilane, such as hexachlorodisilane, pentachlorodisilane, ortetrachlorodisilane, and one or more co-reactant gases to form SiN andSiCN films, as disclosed in PCT Publication Number WO2011/123792, theentire contents of which are incorporated herein in their entireties.

When the desired silicon-containing film also contains another element,such as, for example and without limitation, Ta, Hf, Nb, Mg, Al, Sr, Y,Ba, Ca, As, Sb, Bi, Sn, Pb, Co, lanthanides (such as Er), orcombinations thereof, the co-reactants may include a metal-containingprecursor which is selected from, but not limited to, metal alkyls, suchas Ln(RCp)₃ or Co(RCp)₂, metal amines, such as Nb(Cp)(NtBu)(NMe₂)₃ andany combination thereof.

The organosilane precursor and one or more co-reactants may beintroduced into the reaction chamber simultaneously (chemical vapordeposition), sequentially (atomic layer deposition), or in othercombinations. For example, the organosilane precursor may be introducedin one pulse and two additional metal sources may be introduced togetherin a separate pulse [modified atomic layer deposition]. Alternatively,the reaction chamber may already contain the co-reactant prior tointroduction of the organosilane precursor. The co-reactant may bepassed through a plasma system localized or remotely from the reactionchamber, and decomposed to radicals. Alternatively, the organosilaneprecursor may be introduced to the reaction chamber continuously whileother metal sources are introduced by pulse (pulsed-chemical vapordeposition). In each example, a pulse may be followed by a purge orevacuation step to remove excess amounts of the component introduced. Ineach example, the pulse may last for a time period ranging from about0.01 s to about 10 s, alternatively from about 0.3 s to about 3 s,alternatively from about 0.5 s to about 2 s. In another alternative, theorganosilane precursor and one or more co-reactants may besimultaneously sprayed from a shower head under which a susceptorholding several wafers is spun (spatial ALD).

In one non-limiting exemplary atomic layer deposition type process, thevapor phase of an organosilane precursor is introduced into the reactionchamber, where it is contacted with a suitable substrate. Excessorganosilane precursor may then be removed from the reaction chamber bypurging and/or evacuating the reaction chamber. An oxygen source isintroduced into the reaction chamber where it reacts with the absorbedorganosilane precursor in a self-limiting manner. Any excess oxygensource is removed from the reaction chamber by purging and/or evacuatingthe reaction chamber. If the desired film is a silicon oxide film, thistwo-step process may provide the desired film thickness or may berepeated until a film having the necessary thickness has been obtained.

Alternatively, if the desired film is a silicon metal oxide film (i.e.,SiMO_(x), wherein and x may be 0-4 and M is Ta, Hf, Nb, Mg, Al, Sr, Y,Ba, Ca, As, Sb, Bi, Sn, Pb, Co, lanthanides (such as Er), orcombinations thereof), the two-step process above may be followed byintroduction of a second vapor of a metal-containing precursor into thereaction chamber. The metal-containing precursor will be selected basedon the nature of the silicon metal oxide film being deposited. Afterintroduction into the reaction chamber, the metal-containing precursoris contacted with the substrate. Any excess metal-containing precursoris removed from the reaction chamber by purging and/or evacuating thereaction chamber. Once again, an oxygen source may be introduced intothe reaction chamber to react with the metal-containing precursor.Excess oxygen source is removed from the reaction chamber by purgingand/or evacuating the reaction chamber. If a desired film thickness hasbeen achieved, the process may be terminated. However, if a thicker filmis desired, the entire four-step process may be repeated. By alternatingthe provision of the organosilane precursor, metal-containing precursor,and oxygen source, a film of desired composition and thickness can bedeposited.

Additionally, by varying the number of pulses, films having a desiredstoichiometric M:Si ratio may be obtained. For example, a SiMO₂ film maybe obtained by having one pulse of the organosilane precursor and onepulses of the metal-containing precursor, with each pulse being followedby pulses of the oxygen source. However, one of ordinary skill in theart will recognize that the number of pulses required to obtain thedesired film may not be identical to the stoichiometric ratio of theresulting film.

In another alternative, Si or dense SiCN films may be deposited via anALD or modified ALD process using the disclosed compounds and ahalosilane compound having the formula Si_(a)H_(2a+2−b)X_(b), wherein Xis F, Cl, Br, or I; a=1 through 6; and b=1 through (2a+2); or a cyclichalosilane compound having the formula —Si_(c)H_(2c−d)X_(d)—, wherein Xis F, Cl, Br, or I; c=3-8; and d=1 through 2c. Preferably the halosilanecompound is trichlorosilane, hexachlorodisilane (HCDS),pentachlorodisilane (PODS), tetrachlorodisilane, orhexachlorocyclohexasilane. One of ordinary skill in the art willrecognize that the Cl in these compounds may be substituted by Br or Iwhen lower deposition temperatures are necessary, due to the lower bondenergy in the Si—X bond (i.e., Si—Cl=456 kJ/mol; Si—Br=343 kJ/mol;Si—I=339 kJ/mol). If necessary, the deposition may further utilize anN-containing co-reactant, such as NH₃. Vapors of the disclosedprecursors and the halosilane compounds may be introduced sequentiallyor simultaneously into the reactor, depending on the desiredconcentration of the final film. The selected sequence of precursorinjection will be determined based upon the desired film compositiontargeted. The precursor introduction steps may be repeated until thedeposited layer achieves a suitable thickness. One of ordinary skill inthe art will recognize that the introductory pulses may be simultaneouswhen using a spatial ALD device. As described in PCT Pub NoWO2011/123792, the order of the introduction of the precursors may bevaried and the deposition may be performed with or without the NH₃co-reactant in order to tune the amounts of carbon and nitrogen in theSiCN film.

The silicon-containing films resulting from the processes discussedabove may include SiO₂, SiN, SiON, SiCN, SiCOH, or MSiO_(x), wherein Mis an element such as Hf, Zr, Ti, Nb, Ta, or Ge, and x may be 4,depending of course on the oxidation state of M. One of ordinary skillin the art will recognize that by judicial selection of the appropriateorganosilane precursor and co-reactants, the desired film compositionmay be obtained.

Upon obtaining a desired film thickness, the film may be subject tofurther processing, such as thermal annealing, furnace-annealing, rapidthermal annealing, UV or e-beam curing, and/or plasma gas exposure.Those skilled in the art recognize the systems and methods utilized toperform these additional processing steps. For example, thesilicon-containing film may be exposed to a temperature ranging fromapproximately 200° C. and approximately 1000° C. for a time ranging fromapproximately 0.1 second to approximately 7200 seconds under an inertatmosphere, a H-containing atmosphere, a N-containing atmosphere, an0-containing atmosphere, or combinations thereof. Most preferably, thetemperature is 600° C. for less than 3600 seconds under a H-containingatmosphere. The resulting film may contain fewer impurities andtherefore may have improved performance characteristics. The annealingstep may be performed in the same reaction chamber in which thedeposition process is performed. Alternatively, the substrate may beremoved from the reaction chamber, with the annealing/flash annealingprocess being performed in a separate apparatus. Any of the abovepost-treatment methods, but especially thermal annealing, has been foundeffective to reduce carbon and nitrogen contamination of thesilicon-containing film.

It will be understood that many additional changes in the details,materials, steps, and arrangement of parts, which have been hereindescribed and illustrated in order to explain the nature of theinvention, may be made by those skilled in the art within the principleand scope of the invention as expressed in the appended claims. Thus,the present invention is not intended to be limited to the specificembodiments in the examples given above and/or the attached drawings.

What is claimed is:
 1. A Si-containing thin film forming precursorhaving the following formula:

wherein each L¹ and L² is a nitrogen atom; L¹ and L² being joinedtogether via a carbon bridge having two to three carbon atoms; L¹, L²and the carbon bridge forming a monoanionic ligand bonded to silicon. 2.The Si-containing thin film forming precursor of claim 1, having thefollowing formula:

wherein R¹, R², R³, R⁴, and R⁵ may each independently be H, a C1 to C6alkyl group, or a C3-C20 aryl or heterocycle.
 3. The Si-containing thinfilm forming precursor of claim 2, wherein the Si-containing thin filmforming precursor is H₃Si(-(iPr)N—C₃H₃—N(iPr)-).
 4. The Si-containingthin film forming precursor of claim 1, having the following formula:

wherein R¹, R², R³, R⁴, R⁵, and R⁶ may each independently be H, a C1 toC6 alkyl group, or a C3-C20 aryl or heterocycle.
 5. The Si-containingthin film forming precursor of claim 4, wherein the Si-containing thinfilm forming precursor is H₃Si(-(iPr)N—C₃H₆—N(Me)₂-).
 6. TheSi-containing thin film forming precursor of claim 1, having thefollowing formula:

wherein R¹, R², R³, R⁴, and R⁵ may each independently be H, a C1 to C6alkyl group, or a C3-C20 aryl or heterocycle.
 7. The Si-containing thinfilm forming precursor of claim 6, wherein the Si-containing thin filmforming precursor is H₃Si(-(iPr)N—CH₂CH═N(iPr)-).
 8. The Si-containingthin film forming precursor of claim 1, having the following formula:

wherein R¹, R², R³, R⁴, and R⁵ may each independently be H, a C1 to C6alkyl group, or a C3-C20 aryl or heterocycle.
 9. The Si-containing thinfilm forming precursor of claim 8, wherein the Si-containing thin filmforming precursor is H₃Si((iPr)NC₂H₄N(Me)₂.
 10. A method of depositing aSi-containing layer on a substrate, the method comprising: introducingat least one Si-containing thin film forming precursor of claim 1 into areactor having at least one substrate disposed therein; depositing atleast part of the Si-containing thin film forming precursor onto the atleast one substrate to form a Si-containing layer using a vapordeposition method.
 11. The method of claim 10, further comprisingintroducing into the reactor at least one co-reactant.
 12. The method ofclaim 11, wherein the co-reactant is selected from the group consistingof O₂, O₃, H₂O, H₂O₂, NO, NO₂, a carboxylic acid, radicals thereof, andcombinations thereof.
 13. The method of claim 11, wherein theco-reactant is selected from the group consisting of H₂, NH₃, (SiH₃)₃N,hydridosilanes, chlorosilanes and chloropolysilanes, alkysilanes,hydrazines, organic amines, pyrazoline, pyridine, B-containingmolecules, alkyl metals, radical species thereof, and mixtures thereof.14. The method of claim 13, wherein the co-reactant is selected from thegroup consisting of H₂, NH₃, SiH₄, Si₂H₆, Si₃H₈, SiH₂Me₂, SiH₂Et₂,N(SiH₃)₃, hydrogen radicals thereof, and mixtures thereof.
 15. Themethod of claim 13, wherein the co-reactant is selected from the groupconsisting of SiHCl₃, Si₂Cl₆, Si₂HCl₅, Si₂H₂Cl₄, and cyclo-Si₆H₆Cl₆.